Google Services MCP Server

Instructions

Implementation Reference

• src/finance.ts:425-481 (handler)

  Main handler function that queries SerpAPI for Google Finance data, filters response, optionally fetches additional news from Brave, and formats output to Markdown.

  export async function searchFinance(
    params: z.infer<typeof financeSearchSchema>
  ): Promise<string> {
    const apiKey = process.env.SERP_API_KEY;
    if (!apiKey) {
      throw new Error("SERP_API_KEY environment variable is required");
    }
  
    const {
      include_markets,
      include_discover,
      include_news,
      max_futures,
      summary_only,
      max_news,
      ...apiParams
    } = params;
  
    const searchParams = new URLSearchParams({
      engine: "google_finance",
      api_key: apiKey,
      q: apiParams.q,
      hl: "en",
      ...(apiParams.window && { window: apiParams.window }),
      ...(apiParams.async !== undefined && { async: apiParams.async.toString() }),
    });
  
    try {
      const response = await axios.get<SerpApiFinanceResponse>(
        `${SERPAPI_BASE_URL}?${searchParams.toString()}`
      );
  
      // Check for API errors first
      if (response.data.error) {
        throw new Error(`SerpAPI Error: ${response.data.error}`);
      }
  
      const filteredData = filterFinanceResponse(response.data, params);
  
      // Fetch additional news if requested
      let braveNews: BraveNewsResult[] = [];
      if (max_news && max_news > 1 && include_news !== false) {
        braveNews = await fetchAdditionalNews(params.q, max_news);
      }
  
      return formatFinanceToMarkdown(filteredData, params, braveNews);
    } catch (error) {
      if (axios.isAxiosError(error)) {
        throw new Error(
          `Finance API request failed: ${
            error.response?.data?.error || error.message
          }`
        );
      }
      throw error;
    }
  }

• src/finance.ts:285-328 (schema)

  Zod schema defining input parameters for the finance-search tool, including query, options for markets, news, etc.

  const financeSearchSchema = z.object({
    q: z
      .string()
      .describe(
        "Stock symbol with exchange in format 'SYMBOL:EXCHANGE'. Examples: 'AAPL:NASDAQ', 'TSLA:NASDAQ', 'MSFT:NASDAQ', 'GOOGL:NASDAQ', 'NVDA:NASDAQ' for stocks. For ETFs/Index funds: 'SPY:NYSEARCA', 'VTI:NYSEARCA', 'QQQ:NASDAQ', 'VOO:NYSEARCA'. For crypto: 'BTC-USD', 'ETH-USD'. Note: Just 'SPY' returns market overview with related ETFs in futures_chain."
      ),
    window: z
      .enum(["1D", "5D", "1M", "6M", "YTD", "1Y", "5Y", "MAX"])
      .optional()
      .describe("Time range for graph data"),
    async: z.boolean().optional().describe("Submit search asynchronously"),
    include_markets: z
      .boolean()
      .optional()
      .default(false)
      .describe("Include market overview data"),
    include_discover: z
      .boolean()
      .optional()
      .default(false)
      .describe("Include discover more section"),
    include_news: z
      .boolean()
      .optional()
      .default(true)
      .describe("Include top news"),
    max_futures: z
      .number()
      .optional()
      .default(3)
      .describe("Maximum number of futures chain items to return"),
    summary_only: z
      .boolean()
      .optional()
      .default(true)
      .describe("Return only essential information (price, movement, news)"),
    max_news: z
      .number()
      .optional()
      .default(1)
      .describe(
        "Maximum number of news articles to return (1 = only top news from Google Finance, >1 = additional news from Brave Search)"
      ),
  });

• src/index.ts:120-148 (registration)

  Registration of the finance-search tool on the MCP server, providing description, schema, and wrapper handler that calls searchFinance.

  server.tool(
    "finance-search",
    "Search for stocks, indices, mutual funds, currencies, and futures using Google Finance. Use format 'SYMBOL:EXCHANGE'. Stocks: 'AAPL:NASDAQ', 'TSLA:NASDAQ'. ETFs/Index funds: 'SPY:NYSEARCA', 'VTI:NYSEARCA', 'QQQ:NASDAQ', 'VOO:NYSEARCA'. Crypto: 'BTC-USD', 'ETH-USD'. Note: Query 'SPY' (no exchange) returns market overview with S&P 500 related ETFs.",
    financeSearchSchema.shape,
    async (params) => {
      try {
        const result = await searchFinance(params);
        return {
          content: [
            {
              type: "text",
              text: result,
            },
          ],
        };
      } catch (error) {
        return {
          content: [
            {
              type: "text",
              text: `Error searching finance data: ${
                error instanceof Error ? error.message : String(error)
              }`,
            },
          ],
        };
      }
    }
  );

• src/finance.ts:121-283 (helper)

  Helper function that formats the raw finance API data into a structured Markdown response including price, changes, news, etc.

  function formatFinanceToMarkdown(
    data: any,
    params: z.infer<typeof financeSearchSchema>,
    braveNews: BraveNewsResult[] = []
  ): string {
    if (!data) return "No financial data available.";
  
    let markdown = `# ${params.q}\n\n`;
  
    // Main stock/security info
    if (data.summary) {
      const summary = data.summary;
      const price = summary.price !== undefined ? summary.price : "N/A";
      markdown += `Current Price: ${summary.currency || "$"}${price}  \n`;
  
      if (summary.price_movement) {
        const movement = summary.price_movement;
        const arrow =
          movement.movement === "up"
            ? "📈"
            : movement.movement === "down"
            ? "📉"
            : "➡️";
        markdown += `Change: ${arrow} ${movement.percentage}% (${
          movement.value >= 0 ? "+" : ""
        }${movement.value})  \n`;
      }
  
      if (summary.name && summary.name !== summary.symbol) {
        markdown += `Name: ${summary.name}  \n`;
      }
      markdown += `\n`;
    }
  
    // Price insights
    if (data.price_insights) {
      const insights = data.price_insights;
      markdown += `## Price Analysis\n\n`;
      if (insights.previous_close)
        markdown += `Previous Close: $${insights.previous_close}  \n`;
      if (insights.day_range) markdown += `Day Range: $${insights.day_range}  \n`;
      if (insights.year_range)
        markdown += `52-Week Range: $${insights.year_range}  \n`;
      if (insights.market_cap)
        markdown += `Market Cap: ${insights.market_cap}  \n`;
      if (insights.pe_ratio) markdown += `P/E Ratio: ${insights.pe_ratio}  \n`;
      markdown += `\n`;
    }
  
    // Futures chain (for summary mode)
    if (
      data.futures_chain &&
      params.summary_only &&
      data.futures_chain.length > 0
    ) {
      const futures = data.futures_chain.slice(0, params.max_futures || 3);
      if (futures.length > 1) {
        markdown += `## Futures Contracts\n\n`;
        futures.forEach((future: any) => {
          markdown += `${future.date || future.stock}: $${
            future.price || future.extracted_price
          }`;
          if (future.change) markdown += ` (${future.change})`;
          markdown += `  \n`;
        });
        markdown += `\n`;
      }
    }
  
    // Top news - safely handle different data structures
    if (data.top_news && params.include_news !== false) {
      try {
        let newsItems: any[] = [];
  
        if (Array.isArray(data.top_news)) {
          newsItems = data.top_news;
        } else if (
          data.top_news.results &&
          Array.isArray(data.top_news.results)
        ) {
          newsItems = data.top_news.results;
        } else if (typeof data.top_news === "object") {
          // If it's a single news object, put it in an array
          if (
            data.top_news.title ||
            data.top_news.headline ||
            data.top_news.snippet
          ) {
            newsItems = [data.top_news];
          } else {
            // Try to convert object values to array
            newsItems = Object.values(data.top_news).filter(
              (item: any) =>
                item &&
                typeof item === "object" &&
                (item.title || item.headline || item.snippet)
            );
          }
        }
  
        if (newsItems.length > 0) {
          markdown += `## Latest News\n\n`;
          newsItems.slice(0, 5).forEach((news: any, index: number) => {
            if (news && (news.title || news.headline || news.snippet)) {
              markdown += `### ${index + 1}. ${
                news.title || news.headline || "News Update"
              }\n`;
              if (news.source) markdown += `Source: ${news.source}  \n`;
              if (news.date || news.published_date)
                markdown += `Date: ${news.date || news.published_date}  \n`;
              if (news.snippet || news.description)
                markdown += `${news.snippet || news.description}  \n`;
              if (news.link || news.url)
                markdown += `[Read More](${news.link || news.url})  \n`;
              markdown += `\n`;
            }
          });
        }
      } catch (error) {
        // Silently skip news section if there's an error
      }
    }
  
    // Additional news from Brave Search
    if (braveNews.length > 0 && params.include_news !== false) {
      if (!data.top_news || Object.keys(data.top_news || {}).length === 0) {
        markdown += `## Latest News\n\n`;
      }
  
      braveNews.forEach((news, index) => {
        const newsIndex = data.top_news ? index + 2 : index + 1; // Start after Google Finance news
        markdown += `### ${newsIndex}. ${news.title}\n`;
        if (news.source?.name) markdown += `Source: ${news.source.name}  \n`;
        if (news.published_datetime)
          markdown += `Date: ${news.published_datetime}  \n`;
        if (news.description) markdown += `${news.description}  \n`;
        if (news.url) markdown += `[Read More](${news.url})  \n`;
        markdown += `\n`;
      });
    }
  
    // Market overview (if included)
    if (data.markets && params.include_markets) {
      markdown += `## Market Overview\n\n`;
      if (data.markets.top_news) {
        markdown += `Market News Available: ${data.markets.top_news.length} articles  \n`;
      }
      markdown += `\n`;
    }
  
    // Discover more (if included)
    if (data.discover_more && params.include_discover) {
      markdown += `## Related\n\n`;
      if (data.discover_more.similar_stocks) {
        markdown += `Similar Stocks: ${data.discover_more.similar_stocks
          .map((s: any) => s.stock || s)
          .join(", ")}  \n`;
      }
      markdown += `\n`;
    }
  
    return markdown;
  }